Systematics and biogeography of Appalachian Anillini, and a taxonomic review of the species of South Carolina (Coleoptera, Carabidae, Trechinae, Anillini)

Abstract

In the eastern United States, 74 species of Anillini in two genera have been described, with most belonging to Anillinus Casey. Until now, no systematic framework has existed for this large genus, hampering integrative studies. Using DNA sequences from 101 Nearctic species, we present a well-resolved molecular phylogeny supporting a sound systematic framework. Sixteen species groups of Appalachian Anillinus are diagnosed, in part using newly recognized variation in the number of modified male protarsi and the state of the spermathecal duct. We present the first descriptions of Nearctic anilline larvae, which possess none of the synapomorphies of previously described anilline larvae. Within Anillinus, two major clades are mostly consistent with setation of the right paramere: a “hairy clade” with more than four setae, and a “quadrisetose clade.” Throughout the phylogeny, microhabitat use varies within each clade, and several endogean lineages are phylogenetically isolated. Our work increases the South Carolina fauna by nearly five-fold. Nine new species are described, Serranillus monadnocksp. nov., Anillinus castaneussp. nov., Anillinus choestoeasp. nov., Anillinus dentatussp. nov., Anillinus jancaesp. nov., Anillinus micasp. nov., Anillinus micamicussp. nov., Anillinus senecasp. nov., and Anillinus simplexsp. nov. Several species are newly reported from South Carolina, bringing the total to 20 described species representing seven species groups. Two endemic groups inhabit deep clay soils in the Piedmont and possess unique male sexual characters. The Anillini are a unique component of Nearctic biodiversity, with great potential as a model system for studies of biogeography, secondary male sexual modification, and endogean adaptations.